/**
 * Classname: problem2_Garg
 * 
 * Version: 1.0
 * 
 * Date: 03/10/2009
 * 
 * Author: Dilip Garg
 */

import java.util.Scanner;

/**
 * This class lists all the non negetive even numbers less than 
 * a given number.
 * 
 * Usage: NonNegetiveEven < input.txt > output.txt
 */

public class problem2_Garg
{
	int n;

	/**
	 * Base Constructor
        */
	problem2_Garg()
	{
		n = 0;
	}

	public static void main (String[] args)
	{
		// Read from the standard input
		Scanner sc = new Scanner(System.in);
		int input = sc.nextInt();
	
		// Call the function 
		computeList(input, 0);

		System.out.print("\n");
	}
	
	/**
	 * This method prints the list of all non negetive even numbers
	 * less than the given number onto standard output
	 * @arg1 input number
	 * @arg2 current value of the counter, gets incremented by 2 at every call
	 */
	public static void computeList(int input, int count)
	{
		if (input > count)
		{
			System.out.print(count + " ");
			count += 2;
			computeList(input, count);
		}		
	}
}
